An increase in the number of dimer vacancies on (001)-2 x 1 surfaces after radiation quenching from high temperatures was observed by means of scanning tunnelling microscopy. After further quenches, the vacancies nucleated into chains which ran perpendicularly to the dimer rows. These vacancy chains then connected up and developed into vacancy lines that extended for many hundreds of nm. Each vacancy line consisted mainly of 2 types of dimer vacancy. One was a di-vacancy, and the other was a combination of a single vacancy and a di-vacancy; separated by an isolated dimer. All of the vacancy lines, together with dimer rows, formed a 2 x n structure; where n ranged from 6 to 12.

F.K.Men, A.R.Smith, K.J.Chao, Z.Zhang, C.K.Shih: Physical Review B, 1995, 52[12], R8650-3